Information recording medium, information recording method, information recording apparatus and information reproducing apparatus

ABSTRACT

An information recording medium of the present invention includes: a volume space in which user data is recorded; a spare area including a replacement area which may be used in place of a defective area included in the volume space; and a defect management information area in which defeat management information for managing the defective area is recorded. The defect management information includes status information indicating whether the defective area is replaced by the replacement area.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information recording medium, aninformation recording method, an information recording apparatus and aninformation reproducing apparatus.

2. Description of the Related Art

An optical disk is a type of information recording medium which has asector structure. In recent years, as the recording density and thecapacity of an optical disk have been increased, it has become moreimportant to ensure the reliability thereof. In order to ensure thereliability, an optical disk apparatus performs defect management inwhich a sector on the disk which cannot be used for recordingreproduction (hereinafter, referred to as a "defective sector") isreplaced by another sector having a good condition. One standard forsuch defect management is ISO/IEC 10090 for 90 mm optical disks(hereinafter, referred to as the "ISO standard"), which is publishedfrom International Standards Organization (ISO).

As the first prior art example, an ECC block which is used by a DVDstandard and the defect management method according to the ISO standardwill be briefly described below.

FIG. 17 illustrates a physical structure of a disk 1. The disk 1 has aplurality of tracks 2 provided in the form of concentric circles or aspiral. Each of the tracks 2 is divided into a plurality of sectors 3.The disk 1 includes one or more disk information areas 4 and a datarecording area 5.

The disk information area 4 stores various parameters needed to accessthe disk 1. In the example illustrated in FIG. 17, two disk informationareas 4 are provided respectively along the inner and outer peripheriesof the disk 1. The disk information area 4 along the inner periphery isalso called a "lead-in" area, while the disk information area 4 alongthe outer periphery is also called a "lead-out" area.

Data is recorded/reproduced on/from the data recording area 5. Eachsector 3 in the data recording area 5 is assigned an absolute addresswhich is called a "physical sector number".

FIG. 18A illustrates a structure of an ECC (error correcting code) blockwhich is a unit of error correcting code calculation. An ECC blockcontains main data (172 bytes×48 rows), an inner code parity PI obtainedby calculating error correcting codes for each row (in the horizontaldirection), and an outer code parity PO obtained by calculating errorcorrecting codes for each column (in the vertical direction).

An error correction method using such inner and outer parities isgenerally called a "product code-based error correction method". Theproduct code-based error correction method is an error correction methodwhich is effective for both random errors and burst errors (a group oflocalized errors). For example, consider a case where some random errorsoccurred, as well as two rows of burst errors due to a scratch made onthe disk 1. Most of such burst errors are correctable using the outercodes, because they are 2-byte errors in the vertical direction. Acolumn with many random errors may not completely be corrected by outercodes. Some errors may remain after an error correction operation usingouter codes. However, such remaining errors are in most casescorrectable using inner codes. Even if some errors still remain afterthe error correction operation using inner codes, such errors canfurther be reduced by performing an error correction operation usingouter codes again. By employing such product codes, DVDs realize asufficient error correction capability while saving the parityredundancy. In other words, the capacity for user data is increased bysuch saving of the parity redundancy.

In a larger capacity DVD, each ECC block includes 16 sectors so as torealize both an increased error correction capability and a reducedredundancy. The ECC block illustrated in FIG. 18A includes only 4sectors for the sake of simplicity.

FIG. 18B illustrates an arrangement of sectors included in an ECC block.The outer code parities PO of the ECC block are divided into rows andproportionally distributed among the sectors. As a result, eachrecording sector includes data of 182 bytes×13 rows.

An upper level control unit (this generally corresponds to a hostcomputer) instructs an optical disk apparatus to record or reproducedata by sectors. When instructed to reproduce data from a sector, theoptical disk apparatus reproduces an ECC block including the sector fromthe disk, performs error correction on the reproduced data, and returnsonly a portion of the data which corresponds to the designated sector.When instructed to record data on a sector, the optical disk apparatusreproduces an ECC block including the sector from the disk, performserror correction on the reproduced data, and replaces a portion of thedata which corresponds to the designated sector with recording datawhich has been received from the upper level control unit. Then, theoptical disk apparatus recalculates error correcting codes for the ECCblock and adds them to the ECC block, before the ECC block including thedesignated sector is recorded on the disk. Particularly, such arecording operation is called a "read modified write" operation.

In the following description, a "block" means an ECC block as describedabove.

FIG. 19 illustrates an exemplary physical space of the disk 1 for usewith the defeat management method according to the ISO standard. Thedata recording area 5 includes a volume space 6 and a spare area 9.

The volume space 6 is managed by consecutive addresses, called "logicalsector numbers". The volume space 6 includes a logical volume space 6aand logical volume structures 6b for storing information on thestructure of the logical volume space 6a.

The spare area 9 includes at least one sector (for example, #1 spareblock) which may be used in place of a defective sector if such adefective sector occurs in the volume space 6.

In the example illustrated in FIG. 19, a file A (indicated as "File-A"in FIG. 19) exists directly under a root directory (indicated as "ROOT"in FIG. 19). Among data blocks a to c included in the data extent of theroot directory, the data block c is defective. The defective block c isreplaced by #1 spare block in the spare area 9. Among data blocks d to gincluded in the data extent of the file A, the data block f isdefective. The defective block f is replaced by #2 spare block in thespare area 9.

The replacement of each defective block by a spare block in the sparearea 9 is registered in a secondary defect list ("SDL"). The SDL isstored in a defect management information area as a part of defectmanagement information.

More recently, there is an attempt in the art to use a rewritableoptical disk in a less expensive form of a bare disk with no cartridge,an a read-only optical disk. In view of the defect management, however,a bare disk is more likely to get fingerprints thereon, and the numberof defective sectors may increase unexpectedly. Therefore, it isproposed in the art to use a dynamically expandable spare area ratherthan a fixed spare area.

Moreover, the increased capacity of an optical disk, along with themotion picture compression technique having been put into practical use,has paved the way to recording/reproduction of motion pictures on/froman optical disk. However, the conventional defect management method maynot be suitable for such a motion picture application, in which realtime processing is required. In particular, if a defective sector isreplaced by a spare sector which is physically distant from thedefective sector, it may take too much time to move the optical head tosuch a distant spare sector for ensuring the real time processing.Therefore, it has been proposed in the art to employ a new defectmanagement method instead of the conventional method where a defectivesector is replaced by a physically distant spare sector.

As the second prior art example, a proposed method forrecording/reproducing AV data (i.e., audio video data) will be describedbelow.

Each of FIGS. 20A and 20B illustrates an arrangement of AV data on adisk, which is suitable for AV data recording/reproduction. In FIGS. 20Aand 20B, a suffix "h" denotes a hexadecimal number.

FIG. 20A illustrates an AV data arrangement where there is no defectivesector. If there is no defective sector, the AV data including #1 datato #4 data can be recorded in sectors having consecutive logical sectornumbers (LSN). Similarly, the AV data can be reproduced by reproducingthe sectors having the consecutive logical sector numbers.

FIG. 20B illustrates an AV data arrangement where 16 sectors havinglogical sector numbers of n to n+0Fh are detected as defective sectorswhile recording data therein. In this case, the ECC block including thedetected defective sector is skipped. As a result, #3 data is recordedin sectors having logical sector numbers of n+10h to n+1Fh, and #4 datais recorded in the following sectors having logical sector numbers ofn+20h to n+2Fh. Such an operation of skipping sectors by ECC blocks isreferred to as a "block skip".

FIG. 21 illustrates an exemplary physical space of the disk 1 which issuitable for AV data recording/reproduction.

In the example illustrated in FIG. 21, a file A (indicated as "File-A"in FIG. 21) containing AV data exists directly under a root directory(indicated as "ROOT" in FIG. 21). Among data blocks a to c included inthe data extent of the root directory, the data block c is defective.The defective block c is replaced by #1 spare block in the spare area 9.It is assumed that a defective block f is detected while recording theAV data extent of the file A in an area provided for the AV data extent.In such a case, the defective block f is skipped. As a result, the AVdata extent of the file A is recorded while being divided into an AVdata extent I (including the data blocks d and e) and another AV dataextent II (including the data blocks g and h).

The replacement of the defective block c by #1 spare block in the sparearea 9 is registered in the SDL. However, the defective block f is notregistered in the SDL because the defective block f was only skipped,and the defective block f is not replaced by a spare block (no spareblock has even been allocated thereto).

However, there is a problem associated with the presence of such adefective block which is not registered in the SDL. The problem will bedescribed below with reference to FIGS. 22A to 22C.

FIG. 22A illustrates a normally recorded ECC block. The ECC block isrecorded over a plurality of sectors. Each sector begins with an IDcontaining the physical sector number of the sector, etc. Data isrecorded in the area following the ID. The data is obtained by addingerror correcting codes to main data and further interleaving the maindata having the error correcting codes added thereto (see FIG. 18).

FIG. 22B illustrates an ECC block for which an overwrite operationfailed. When the ECC block illustrated in FIG. 22A is overwritten withnew data, new error correcting codes are calculated according to the newmain data, and added to the ECC block. In the example illustrated inFIG. 22B, however, the third sector has a defective ID. Therefore, thefirst two sectors are overwritten with data of a now ECC block, whilethe other two sectors remain to have the data of an old ECC block.

FIG. 22C illustrates the structure of reproduced data from the ECC blockfor which the overwrite operation failed. When the four sectorsillustrated in FIG. 22B are reproduced, the new data and the old dataare mixed with each other (in FIG. 22C, the new data and the old dataare hatched in different directions). This means that an errorcorrection always fails in the vertical direction using the outer codeparity PO.

As can be appreciated from the description above, a block for which arecording operation even once failed becomes a block from which datacannot be reproduced. The read modified write operation is required torecord data in some sectors of this block. However, a read modifiedwrite operation for such an unreproducible block will always fail. Thus,this block becomes a block on which data can no longer be recorded. Sucha block cannot later be replaced by a replacement block because data tobe transferred to the replacement block cannot be reproduced from theblock, as in the read modified write operation.

If the dynamically expandable spare area was used with the ISO standarddefect management method which is designed for use with a fixed-sizespare area, the spare area may temporarily be exhausted (i.e., noavailable spare area), which would never happen in the conventionaltechniques. There is no method proposed in the art to manage a defectiveblock which is detected while the spare area is temporarily exhausted.Since a read modified write operation for such an unmanaged defectiveblock fails, data cannot be recorded by sectors in the defective block.

Also when recording/reproducing AV data on/from the disk, a readmodified write operation for a skipped defective block fails, therebyexperiencing the same problem as just described above.

SUMMARY OF THE INVENTION

According to one aspect of this invention, an information recordingmedium includes: a volume space in which user data is recorded; a sparearea including a replacement area which may be used in place of adefective area included in the volume space; and a defect managementinformation area in which defect management information for managing thedefective area is recorded. The defect management information includesstatus information indicating whether the defective area is replaced bythe replacement area.

In one embodiment of the invention, when a recording operation of theuser data for the defective area is skipped, the status informationindicating that the defective area is not replaced by the replacementarea is written in the defect management information area.

In one embodiment of the invention, the spare area is an expandablearea. When there are no available spare area in the replacement areatemporarily, the status information indicating that the defective areais not replaced by the replacement area is written in the defectmanagement information area.

In one embodiment of the invention, the defect management informationincludes first location information indicating a location of thedefective area and second location information indicating a location ofthe replacement area. The status information indicates whether thedefective area is replaced by the replacement area based on whether avalue of the second location information is equal to a predeterminedvalue.

In one embodiment of the invention, the defect management informationincludes first location information indicating a location of thedefective area, second location information indicating a location of thereplacement area, and a flag indicating whether the defective area isreplaced by the replacement area. The status information indicateswhether the defective area is replaced by the replacement area based ona value of the flag.

In one embodiment of the invention, the defective area is detected byECC blocks each of which is a unit of an error correction operation. Thedefective area is replaced by the replacement area by ECC blocks.

According to another aspect of this invention, an information recordingmethod for recording information on an information recording medium isprovided. The information recording medium includes: a volume space inwhich user data is recorded; a spare area including a replacement areawhich may be used in place of a defective area included in the volumespace; and a defect management information area in which defectmanagement information for managing the defective area is recorded. Themethod includes the steps of: detecting the defective area; andrecording status information indicating whether the defective area isreplaced by the replacement area in the defect management informationarea.

In one embodiment of the invention, the method further includes the stepof skipping a recording operation of the user data for the defectivearea. When the recording operation of the user data for the defectivearea is skipped, the status information indicating that the defectivearea is not replaced by the replacement area is written in the defectmanagement information area.

In one embodiment of the invention, the spare area is an expandablearea. The method further includes the step of detecting that the sparearea temporarily runs out of available replacement areas. When there areno available spare area in the replacement area temporarily, the statusinformation indicating that the defective area is not replaced by thereplacement area is written in the defect management information area.

In one embodiment of the invention, the defect management informationincludes first location information indicating a location of thedefective area and second location information indicating a location ofthe replacement area. The status information indicates whether thedefective area is replaced by the replacement area based on whether avalue of the second location information is equal to a predeterminedvalue.

In one embodiment of the invention, the defect management informationincludes first location information indicating a location of thedefective area, second location information indicating a location of thereplacement area, and a flag indicating whether the defective area isreplaced by the replacement area. The status information indicateswhether the defective area is replaced by the replacement area based ona value of the flag.

In one embodiment of the invention, the defective area is detected byECC blocks each of which is a unit of an error correction operation. Thedefective area is replaced by the replacement area by ECC blocks.

According to still another aspect of this invention, an informationrecording apparatus for recording information on an informationrecording medium is provided. The information recording medium includes:a volume space in which user data is recorded; a spare area including areplacement area which may be used in place of a defective area includedin the volume space; and a defect management information area in whichdefect management information for managing the defective area isrecorded. The apparatus includes: a detection section for detecting thedefective area; and a recording section for recording status informationindicating whether the defective area is replaced by the replacementarea in the defect management information area.

In one embodiment of the invention, the apparatus further comprises askip section for skipping a recording operation of the user data for thedefective area. When the recording operation of the user data for thedefective area is skipped, the recording section writes in the defectmanagement information area the status information indicating that thedefective area is not replaced by the replacement area.

In one embodiment of the invention, the spare area is an expandablearea. The apparatus further includes a further detection section fordetecting that the spare area temporarily runs out of availablereplacement areas. When there are no available spare area in thereplacement area temporarily, the recording section writes in the defectmanagement information area the status information indicating that thedefective area is not replaced by the replacement area.

In one embodiment of the invention, the defect management informationincludes first location information indicating a location of thedefective area and second location information indicating a location ofthe replacement area. The status information indicates whether thedefective area is replaced by the replacement area based on whether avalue of the second location information is equal to a predeterminedvalue.

In one embodiment of the invention, the defect management informationincludes first location information indicating a location of thedefective area, second location information indicating a location of thereplacement area, and a flag indicating whether the defective area isreplaced by the replacement area. The status information indicateswhether the defective area is replaced by the replacement area based ona value of the flag.

In one embodiment of the invention, the defective area is detected byECC blocks each of which is a unit of an error correction operation. Thedefective area is replaced by the replacement area by ECC blocks.

According to still another aspect of this invention, an informationreproducing apparatus for reproducing information recorded on aninformation recording medium is provided. The information recordingmedium includes: a volume space in which user data is recorded; a sparearea including a replacement area which may be used in place of adefective area included in the volume space; and a defect managementinformation area in which defect management information for managing thedefective area is recorded. The defect management information includesstatus information indicating whether the defective area is replaced bythe replacement area. The apparatus includes: a determination sectionfor determining whether the defective area is replaced by thereplacement area with reference to the status information; and a controlsection for controlling a reproducing operation of the user dataaccording to the determination.

In one embodiment of the invention, when the defective area is notreplaced by the replacement area, the control section skips areproducing operation for the defective area.

In one embodiment of the invention, when the defective area is notreplaced by the replacement area, the control section outputs datahaving a fixed value as data obtained by reproducing the defective area,regardless of data in the defective area.

In one embodiment of the invention, the defective area is detected byECC blocks each of which is a unit of an error correction operation. Thedefective area is replaced by the replacement area by ECC blocks. Theerror correction operation includes a first error correction operationfor correcting errors within a single sector and a second errorcorrection operation for correcting errors over a plurality of sectors.When the defective area is not replaced by the replacement area, thecontrol section performs the first error correction operation, withoutperforming the second error correction operation, for data in thedefective area so as to output data which is corrected by the firsterror correction operation.

Thus, the invention described herein makes possible the advantages of:(1) providing an information recording medium where it is possible tomanage a defective block even when there is no spare block available toreplace the defective block so as to reduce the risk that the readmodified write operation fails, thereby increasing the reliability; (2)providing an information recording method having such a feature; (3)providing an information recording apparatus having such a feature; and(4) providing an information reproducing apparatus having such afeature.

These and other advantages of the present invention will become apparentto those skilled in the art upon reading and understanding the followingdetailed description with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagram illustrating a structure of a physical space of adisk 1 which is an information recording medium according to Embodiment1 of the present invention;

FIG. 1B is a diagram illustrating a structure of an SDL 13 illustratedin FIG. 1A;

FIG. 1C is a diagram illustrating a structure of an SDL entry 22 in theSDL 13;

FIG. 1D is a diagram illustrating another structure of the SDL entry 22in the SDL 13;

FIG. 1E is a diagram illustrating another structure of the SDL entry 22in the SDL 13;

FIG. 2 is a diagram illustrating an exemplary physical space of the disk1 where a file A containing AV data is recorded on the disk 1;

FIG. 3 is a diagram illustrating an exemplary physical space of the disk1 where the file A containing AV data and then a file B containingnon-AV data are recorded on the disk 1;

FIG. 4 is a diagram illustrating an exemplary physical space of the disk1 where the spare area is temporarily exhausted (i.e., out of availablereplacement areas);

FIG. 5 is a diagram illustrating an exemplary physical space of the disk1 where a file C recording operation is retried after expanding a secondspare area 8;

FIG. 6 is a conceptual diagram illustrating a principle of recording AVdata on, or reproducing recorded AV data from, the disk 1;

FIG. 7 is a block diagram illustrating a structure of an informationrecording/reproducing system 700 according to Embodiment 2 of thepresent invention;

FIG. 8 is a diagram illustrating a procedure of a method for recording afile containing AV data on the disk 1 using the informationrecording/reproducing system 700;

FIG. 9 is a diagram illustrating a procedure of a method for reproducinga file containing AV data recorded on the disk 1 using the informationrecording/reproducing system 700;

FIG. 10 is a block diagram illustrating a structure of a diskrecording/reproducing drive 1020 according to Embodiment 3 of thepresent invention;

FIG. 11 is a procedure of a method for reproducing normal computer data(not real time data) recorded on the disk 1 using the diskrecording/reproducing drive 1020;

FIG. 12 is a flow chart illustrating a procedure of a reproducingoperation performed by the disk recording/reproducing drive 1020;

FIG. 13 is a flow chart illustrating a procedure of a recordingoperation performed by the disk recording/reproducing drive 1020;

FIG. 14 is a block diagram illustrating a structure of a diskrecording/reproducing drive 1420 according to Embodiment 4 of thepresent invention;

FIG. 15 is a flow chart illustrating a procedure of a reproducingoperation performed by the disk recording/reproducing drive 1420;

FIG. 16 is a flow chart illustrating a procedure of a recordingoperation performed by the disk recording/reproducing drive 1420;

FIG. 17 is a diagram illustrating a physical structure of the disk 1;

FIG. 18A is a diagram illustrating a structure of an ECC block which isa unit of error correcting code calculation;

FIG. 18B illustrates an arrangement of sectors included in an ECC block;

FIG. 19 illustrates an exemplary physical space of the disk 1 for usewith a defect management method according to the ISO standard;

FIG. 20A illustrates an arrangement of AV data where there is nodefective sector;

FIG. 20B illustrates an arrangement of AV data where there is adefective sector;

FIG. 21 illustrates an exemplary physical space of the disk 1 which issuitable for AV data recording/reproduction;

FIG. 22A is a diagram illustrating a normally recorded ECC block;

FIG. 22B is a diagram illustrating an ECC block for which an overwriteoperation failed;

FIG. 22C is a diagram illustrating a structure of reproduced data froman ECC block for which an overwrite operation failed;

FIG. 23A is a diagram illustrating an exemplary format for a "SKIPWRITE" command;

FIG. 23B is a diagram illustrating another exemplary format for a "SKIPWRITE" command;

FIG. 24A is a diagram illustrating an exemplary format for a "REPORTSKIPPED ADDRESS" command; and

FIG. 24B is a diagram illustrating an exemplary format for data which isreported in response to a "REPORT SKIPPED ADDRESS" command.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Various embodiments of the present invention will be described belowwith reference to the figures.

(Embodiment 1)

A disk 1 is a rewritable information recording medium. The disk 1 may beany type of information recording medium, including a DVD-RAM. Data canbe recorded on the disk 1. The data recorded on the disk 1 can bereproduced therefrom. The recording and reproduction of the data isperformed by sectors or by blocks.

The physical structure of the disk 1 is the same as that illustrated inFIG. 17, and therefore will not further be described below.

FIG. 1A illustrates a structure of the physical space of the disk 1. Thedisk 1 includes one or more disk information areas 4 and a datarecording area 5. In the example illustrated in FIG. 1A, two diskinformation areas 4 are provided respectively along the inner and outerperipheries of the disk 1. The disk information area 4 along the innerperiphery is also called a "lead-in" area, while the disk informationarea 4 along the outer periphery is also called a "lead-out" area.

Data is recorded/reproduced on/from the data recording area 5. Eachsector in the data recording area 5 is assigned an absolute addresswhich is called a physical sector number (hereinafter, abbreviated as a"PSN").

The data recording area 5 includes a volume space 6 and a first sparearea 7.

The volume space 6 is an area provided for storing user data. Eachsector included in the volume space 6 is assigned a logical sectornumber (hereinafter, abbreviated as an "LSN") for accessing the volumespace 6. Data is recorded/reproduced by accessing each sector of thedisk 1 using LSN.

The first spare area 7 includes at least one sector which may be used inplace of a defective sector if such a defective sector occurs in thevolume space 6. The first spare area 7 is arranged on the innerperiphery side of the disk 1 with respect to the volume space 6, so thatwhen a defective sector occurs in an area storing the file managementinformation (free space management information, the file entry of theroot directory. etc.), such a defective sector can be replaced quickly.The file management information is stored near the sector which isassigned an LSN "0". Thus, by arranging the first spare area 7 on theinner periphery side of the disk 1 with respect to the volume space 6,the seek distance between a defective sector and a replacement sectorcan be reduced. In this way, the speed of the defective sectorreplacement process is increased. Since the file management informationis frequently accessed, the file management information requires highdata reliability. Therefore, it is quite effective to quickly replace adefective sector which occurs in the area storing the file managementinformation.

The volume space 6 includes a logical volume space 6a and logical volumestructures 6b for storing information on the structure of the logicalvolume space 6a. The logical volume space 6a stores free spacemanagement information indicating whether a sector in the logical volumespace 6a is used or free, one or more data extents storing the contentsof the file, and a file entry in which one or more data extentscorresponding to the file are registered. Each file is managed by usingthe various types of information.

The disk information area 4 includes a control data area 4a and a defectmanagement information area 4b. The defect management information area4b stores defect management information 10 for managing defectivesectors.

The defect management information 10 includes a disk definitionstructure 11, a primary defect list (hereinafter, abbreviated as a"PDL") 12 and a secondary defect list (hereinafter, abbreviated as an"SDL") 13.

The PDL 12 is used to manage defective sectors which are detected duringa pre-shipping inspection of the disk 1. The pre-shipping inspection ofthe disk 1 is usually conducted by the manufacturer of the disk 1.

The SDL 13 is used to manage defective sectors which are detected duringuse of the disk 1 by a user.

FIG. 1B illustrates a structure of the SDL 13.

The SDL 13 includes: a secondary defect list header ("SDL header") 20containing an identifier which identifies the list as an SDL; number ofSDL entries information 21 indicating the number of SDL entriesregistered in the SDL; and one or more SDL entries 22 (1st entry tom^(th) entry in the example illustrated in FIG. 1B). The number of SDLentries information 21 being "0" indicates that there is no defectivesector registered in the SDL.

FIG. 1C illustrates a structure of the SDL entry 22.

The SDL entry 22 includes a status field 22a, a field 22b for storinginformation which indicates the location of the defective sector, and afield 22c for storing information which indicates the location of areplacement sector for the defective sector.

The status field 22a is used to indicate whether the defective sector isreplaced by a replacement sector. The location of the defective sectoris represented by, for example, the PSN of the defective sector. Thelocation of the replacement sector is represented by, for example, thePSN of the replacement sector.

For example, the statue field 22a may include a 1-bit flag 22a-1 and areserved area 22a-2. For example, the 1-bit flag 22a-1 being "1" mayindicate that the defective sector is not replaced by a replacementsector, and it being "0" may indicate that the defective sector isreplaced by a replacement sector.

Alternatively, the status field 22a may include a 1-bit exhaustion flag22a-3, a 1-bit AV flag 22a-4 and a reserved area 22a-5 (see FIG. 1D).Each of the exhaustion flag 22a-3 and the AV flag 22a-4 is a flagindicating the reason why the defective sector is not replaced by areplacement sector. For example, the exhaustion flag 22a-3 being "1" mayindicate that the defective vector is not replaced by a replacementsector because the first spare area 7 is exhausted. For example, the AVflag 22a-4 being "1" may indicate that the defective sector is notreplaced by a replacement sector because it is a defective sector whichwas detected while recording AV data on the disk 1.

Instead of providing the status field 22a, a predetermined value, whichindicates that "no replacement sector available i.e., the defectivesector is not replaced by a replacement sector)", may alternatively beinserted in the field 22a which is for storing information indicatingthe location of a replacement sector (see FIG. 1E). The predeterminedvalue may be "0", for example.

FIGS. 1C to 1E are only exemplary, and the format for the SDL entry 22is not limited to those illustrated in FIGS. 1C to 1E. The SDL entry 22may take any format as long as the SDL includes the status informationwhich indicates whether the defective sector is replaced by areplacement sector.

For example, by setting the field 22c to a predetermined value while thestatus field 22a is being "1", it is possible to increase the number ofstatuses which can be distinguished from one another. For example, thefield 22c being set to "0" may indicate that a newly detected defectivesector is not replaced by a replacement sector, and the replacementsector has not been assigned. For example, the field 22c being set to avalue other than "0" may indicate that a previously detected defectivesector was replaced by the replacement sector, that is specified by thefield 22c, but the replacement is cancelled.

While the defect management is performed by sectors in theabove-described example, the defect management may alternatively beperformed by blocks each including a plurality of sectors. In such acase, information indicating the location of a defective block (ratherthan a defective sector; e.g., the PSN of the leading sector of thedefective block), and information indicating the location of areplacement block (rather than a replacement sector; e.g., the PSN ofthe leading sector of the replacement block) may be registered in theSDL. It is alternatively possible to perform defect management by ECCblocks each of which is a unit of an error correction operation.

Thus, by storing in the defect management information area, statusinformation which indicates whether a defective area (a defective sectoror a defective block) is replaced by a replacement area (a replacementsector or a replacement block), it is possible to manage the statuswhere a defective area has been detected but is not replaced by areplacement area.

FIG. 2 illustrates an exemplary physical space of the disk 1 where afile A containing AV data is recorded on the disk 1.

In the example illustrated in FIG. 2, a file A (indicated as "File-A" inFIG. 2) exists directly under a root directory (indicated as "ROOT" inFIG. 2). Among data blocks a to c included in the data extent of theroot directory, the data block c is defective. The defective block c isreplaced by #1 spare block in the first spare area 7. It is assumed thata defective block f is detected while recording the AV data extent ofthe file A in an area provided for the AV data extent. In such a case,the defective block f is skipped. As a result, the AV data extent of thefile A is recorded while being divided into an AV data extent I (File-A)(including the data blocks d and e) and another AV data extent II(File-A) (including the data blocks g and h).

The first SDL entry 22 in the SDL 13 indicates that the defective blockc is replaced by #1 spare block in the first spare area 7.

The second SDL entry 22 in the SDL 13 indicates that the defective blockf (which was detected while recording AV data on the disk 1 and thusskipped) is not replaced by a replacement block.

FIG. 3 illustrates an exemplary physical space of the disk 1 where thefile A containing AV data and then a file B containing non-AV data(i.e., a type of data other than AV data) are recorded on the disk 1.

In the example Illustrated in FIG. 3, the defective block f isdesignated as a location where the data extent of the file B is to berecorded. As a result, the defective block f is replaced by #2 spareblock in the first spare area 7. Along with this replacement process,the value in the status field 22a of the second SDL entry 22 in the SDL13 is changed from "1" to "0", and information which indicates thelocation of #2 spare block is stored in the field 22c thereof.

It is assumed that the size of the data extent of the file B is equal tothe size of one block. The structure information of the data extent ofthe file B is described in the file entry of the File B. LSNscorresponding to the file B are described as "used" in the free spacemanagement information. The file B is registered in the data extent ofthe root directory.

If the optical disk apparatus attempts to record data in some sectors ofthe defective block f, not knowing that the defective block f is adefective block for which an AV data recording operation failed, theresult will not be the same as described above for the following reason.The optical disk apparatus performs a read modified write operation soas not to change data in other sectors belonging to the same ECC blockas the sector for which a recording operation is requested. The opticaldisk apparatus attempts to perform the data reproduction step of theread modified write operation in the ECC block, but always fails. As aresult, it is not possible to obtain data in the unit of ECC blocks, asrequired to record the data in a spare block. Thus, replacement cannoteven be made.

If the optical disk apparatus knows that the defective block f is adefective block for which an AV data recording operation failed, it candetermine that no effective user data is recorded in the defective blockf. Such a determination can be made because AV data, which is requiredto be recorded in a real time manner, needs to be recorded on the disk 1by ECC blocks. in other words, the optical disk apparatus is neverrequested to rewrite only some of the sectors in an ECC block.Therefore, a read modified write operation (for rewriting only thesector for which a recording operation is requested without changingdata in the other sectors belonging to the same ECC block) is notrequired for a skipped defective block. Thus, it is possible to createan ECC block by filling the other sectors with "0"s and to record thecreated ECC block in a replacement spare block.

FIG. 4 illustrates an exemplary physical space of the disk 1 where thespare area is temporarily exhausted (i.e., out of available replacementareas).

As compared to the physical space illustrated in FIG. 2, an expandablesecond spare area 8 is additionally allocated in the data recording area5. Along with the allocation of the second spare area 8, the size of thevolume space 6 and the size of the logical volume space 6a are reducedaccording to the size of the second spare area 8. Prior to theallocation of the second spare area 8, the volume structure 6b along theouter periphery of the disk 1 is moved toward the inner periphery of thedisk 1. The size of the free space management information is adjustedaccording to the size of the logical volume space 6a.

in the example illustrated in FIG. 4, a file A (indicated as "File-A" inFIG. 4), a file B (indicated as "File-B" in FIG. 4), and a file C(indicated as "File-C" in FIG. 4), which is now being recorded, existdirectly under a root directory (indicated as "ROOT" in FIG. 4).

A data block c included in the data extent of the root directory isdefective. The defective block c is replaced by #1 spare block in thefirst spare area 7.

A data block f included in the data extent of the file A is defective.The data block f is replaced by #2 spare block in the first spare area7.

Data blocks h and j included in the data extent of the file B aredefective. The data blocks h and j are replaced respectively by #3 spareblock and #4 spare block in the second spare area 8. When a data block mwas to be recorded as the data extent of the file C, the data block mwas detected as a defective block during the recording operation, and noavailable spare block existed in the first spare area 7 or in the secondspare area 8. Thus, the file C is incomplete.

As compared to the structure of the SDL 13 illustrated in FIG. 1B, theSDL 13 is additionally provided with a field 23 for storing informationwhich indicates the location of the second spare area 8. For example,the PSN of the leading sector of the second spare area 8 may be storedin the field 23 as the information indicating the location of the secondspare area 8. The field 23 is provided for dynamically expanding thesecond spare area 8.

The first SDL entry 22 in the SDL 13 indicates that the defective blockc is replaced by #1 spare block in the first spare area 7.

The second SDL entry 22 in the SDL 13 indicates that the defective blockf is replaced by #2 spare block in the first spare area 7.

The third SDL entry 22 in the SDL 13 indicates that the defective blockh is replaced by #3 spare block in the second spare area 8.

The fourth SDL entry 22 in the SDL 13 indicates that the defective blockj is replaced by #4 spare block in the second spare area 8.

The fifth SDL entry 22 in the SDL 13 indicates that the defective blockm is not replaced by a spare block.

FIG. 5 illustrates an exemplary physical space of the disk 1 where thefile C recording operation is retried after expanding the second sparearea 8.

As illustrated in FIG. 5, the second spare area 8 has been expanded. Thesize of the volume space 6 and the size of the logical volume space 6aare reduced according to the expansion of the second spare area 8.

Prior to the expansion of the second spare area 8, the volume structure6b along the outer periphery of the disk 1 is moved toward the innerperiphery of the disk 1. The size of the free space managementinformation is adjusted according to the size of the logical volumespace 6a.

The data block m included in the data extent of the file C is replacedby #5 spare block in the expanded second spare area 8. The data extentof the file C includes three data blocks l, m and n. The structureinformation of the data extent of the file C is described in the fileentry of the file C. LSNs corresponding to the file C are described as"used" in the free space management information. The file C isregistered in the data extent of the root directory.

The fifth SDL entry 22 in the SDL 13 indicates that the data block m isreplaced by #5 spare block in the expanded second spare area 8.

Unlike when an AV data recording operation fails, when a non-AV datarecording operation fails, the defective block may contain effectiveuser data. A recovery process for such a defective block is somewhatmore complicated than in the case where the defective block does notcontain effective user data.

It is assumed that the optical disk apparatus is requested to recorddata in a sector included in a defective block (ECC block) to which noreplacement block has been allocated. In such a case, the optical diskapparatus reproduces data from the other sectors in the ECC block whichincludes the sector by using only the inner code parities PI (see FIG.22C) which are independently provided for the respective sectors, andperforms a read modified write operation using the reproduced data.

In this way, although the error correction capability is reduced becausethe outer code parity PO is not used, it is possible to correct errorsto the extent the errors are correctable only with the inner code parityPI.

Where a defective block to which no replacement block has been allocatedis registered in the SDL only when there is no effective user data inthe defective block, a defective block recovery process to be performedis similar to that described above which is performed after failure ofan AV data recording operation.

As described above, when a defective area is detected while recordingdata which requires real time processing (e.g., AV data). the data isnot recorded in the defective area (i.e., the defective area isskipped). The location of the defective area is written in the defectmanagement information area 4b of the disk 1. Moreover, statusinformation indicating that the defective area is not replaced by areplacement area is also written in the defect management informationarea 4b of the disk 1. When it is requested to record data which doesnot require real time processing (e.g., non-AV data) in the defectivearea, the defective area is replaced by a replacement area withoutperforming a read modified write operation. The location of thereplacement area is written in the defect management information area 4bof the disk 1.

Thus, by replacing a defective area with a replacement area whileavoiding a read modified write operation which is known to always fall,it is possible to successfully record data which does not require realtime processing in the replacement area.

Moreover, a replacement area is not allocated to a defective area untilit is actually requested to record data in the defective area. Thisprovides an advantage in that no replacement area is wasted.

Where a spare area is expandable, the spare area may temporarily run outof available replacement areas. When no replacement area can beallocated to a detected defective area because the spare area istemporarily out of available replacement areas, the location of thedefective area is written in the defect management information area 4bof the disk 1. Moreover, status Information indicating that thedefective area is not replaced by a replacement area (no replacementarea has been allocated thereto) is written in the defect managementinformation area 4b of the disk 1. After the spare area is expanded anda replacement area is made available, the replacement area is allocatedto the defective area and the defective area is replaced by thereplacement area. The location of the replacement area is written in thedefect management information area 4b of the disk 1.

in the above-described information recording medium, a replacement areais not allocated to a defective area upon detection of the defectivearea, but it is allocated thereto only when effective data is recordedin a logical volume space which corresponds to the defective area. Suchan information recording medium has an advantage in that the spare areacan be efficiently used.

Moreover, the advantage of efficiently using the spare area is notdependent upon the structure of the error correcting code which requiresa read modified write operation.

(Embodiment 2)

An embodiment of an information recording/reproducing system forrecording information on, or reproducing recorded information from, thedisk 1 as described in Embodiment 1 above will now be described withreference to the figures.

FIG. 6 is a conceptual diagram illustrating a principle of recording AVdata on, or reproducing recorded AV data from, the disk 1.

AV data is recorded on the disk 1 with reference to the free spacemanagement information in the logical volume space. The system searchesfor a free area in the logical volume space based on the free spacemanagement information. The number of blocks of the continuously freearea needs to be greater than the number of blocks required for the AVdata to be recorded by at least a predetermined number. Thepredetermined number corresponds to the number of blocks for which askip operation is to be allowed. When a free area satisfying such acondition is found, the free area is allocated to the AV data.

In the example illustrated in FIG. 6, a free area 62 included in an area61 is allocated to AV data 63. The area 61 is a part of the logicalvolume space 6a. The free area 62 includes blocks B₁ to B₁₀.

Parameters for a skip recording instruction are produced based on thesize of the free area 62 which is allocated to the AV data 63 (i.e., thesize of the allocated area) and the size of the AV data 63 (i.e., the AVdata size).

Reference numeral 65 denotes a recording operation performed when a skiprecording instruction is executed.

Defective block detection is performed while recording the AV data 63 inthe free area 62. The AV data 63 is recorded in the free area 62 whileskipping each defective block detected. In the example illustrated inFIG. 6, the blocks B₄ and B₇ are defective. Therefore, a portion of theAV data 63 is recorded in the blocks B₁ -B₂, another portion of the AVdata 63 is recorded in the blocks B₅ -B₆, and the remaining portion ofthe AV data 63 to recorded in the blocks B₈ -B₉. Following the AV data63, padding data 64 is recorded in the block B₉. The padding data 64 isprovided so that the end of the padding data 64 coincides with a blockboundary. As a result of the recording operation, the blocks B₁ -B₃, B₅-B₆ and B₈ -B₉ become "used", while the other blocks B₄, B₇ and B₁₀remain "free".

The locations of the defective blocks B₄ and B₇ are stored in a defectlist 66a. The contents of the defect list 66a are written in the SDL 13in the defect management information area 4b of the disk 1 at anyappropriate time, and are reported to the file system as a skip list 66bas necessary. Based on the reported skip list 66b, the file systemdetermines the location of an AV data extent 66c which indicates thearea where the AV data 63 is recorded, and the location of a paddingextent 66d which indicates the ECC block fraction (i.e., sectors havingno AV data in an ECC block partially including AV data), so as to updatethe file management information.

Parameters for a skip reproducing instruction include the size of theallocated area and the AV data size.

Reference numeral 67 denotes a reproducing operation performed when askip reproducing instruction is executed.

The AV data 63 recorded on the disk 1 is reproduced with reference tothe SDL 13. The AV data 63 is reproduced while skipping the defectiveblocks registered in the SDL 13.

FIG. 7 is a block diagram illustrating a structure of an informationrecording/reproducing system 700 according to Embodiment 2 of thepresent invention.

As illustrated in FIG. 7, the information recording/reproducing system700 includes: an upper level control unit 710 for controlling theoverall system; a disk recording/reproducing drive 720 for controllingthe recording/reproduction of the rewritable disk 1 (not shown in FIG.7) according to the instruction from the upper level control unit 710; amagnetic disk apparatus 750; an AV data output section 760 forconverting digital AV data to an analog AV signal and outputting theanalog AV signal; an AV data input section 770 for converting the inputanalog AV signal to digital AV data; and an I/O bus 780 forreceiving/transmitting data and control information.

The upper level control unit 710 includes a microprocessor in which acontrol program and an arithmetic memory are provided. The upper levelcontrol unit 710 further includes: a recording area allocation section711 for allocating a recording area when recording data; a filemanagement information creation section 712 for creating file managementinformation for each recorded file; a file management informationinterpretation section 713 for calculating the location where the fileis recorded and determining the attribute information of the file basedon the file management information; a data buffer memory 714 fortemporarily storing data; and an instruction issuing section 715 forissuing an instruction to the disk recording/reproducing drive 720.

The instruction issuing section 715 includes: a skip recordinginstruction issuing section 716 for issuing a skip recording instructionwhich requests data to be recorded while skipping defective areas; arecording location request instruction issuing section 717 for issuing arecording location request instruction which requests recording locationinformation to be returned (the information is used after data isrecorded to determine the area where the data has been recorded); and askip reproducing instruction issuing section 718 for issuing a skipreproducing instruction which requests data to be reproduced whileskipping defective areas.

The disk recording/reproducing drive 720 includes a microprocessor inwhich a control program and an arithmetic memory are provided. The diskrecording/reproducing drive 720 is made of a mechanical section, asignal processing circuit, etc., which are controlled by themicroprocessor. The disk recording/reproducing drive 720 operativelyincludes: an instruction processing section 721 for processing aninstruction from the upper level control unit 710; a recording controlsection 730 for controlling the recording operation on the rewritabledisk 1; and a reproduction controlling section 740 for controlling thereproducing operation from the rewritable disk 1.

The instruction processing section 721 includes: a skip recordinginstruction processing section 722 for processing a skip recordinginstruction; a recording location request instruction processing section723 for processing a recording location request instruction; and a skipreproducing instruction processing section 724 for processing a skipreproducing instruction.

The recording control section 730 includes: a defective area detectionsection 731 for detecting a defective area during a recording operation;a skip recording controlling section 732 for recording data whileskipping defective areas which are detected during the recordingoperation; a recording location storing memory 733 for storinginformation relating to the location where data is recorded; a dataverifying section 734 for reading out recorded data so as to determinewhether the data has been normally recorded; a recording controlinformation memory 735 for storing control information (e.g., therecording start location, and the recording length) which is requiredwhen recording data; a recording data storing memory 736 for temporarilystoring recording data received from the upper level control unit 710;and a skip location recording section 737 for recording a defectivearea, which has been detected and skipped during a recording operation,in the defect management information.

The reproduction controlling section 740 includes: a reproductionlocation storing memory 743 for storing information relating to thelocation from which data is reproduced; a skip reproduction controllingsection 742 for reproducing data while skipping defective areas withreference to the reproduction location storing memory 743; areproduction control information memory 745 for storing controlinformation (e.g., the reproduction start location, and the reproductionlength) which is required when reproducing data; a read-out data storingmemory 746 for temporarily storing data which has been read out from therewritable disk 1; and a skip location reading section 747 for readingout the location of a defective area to be skipped from the defectmanagement information and storing it in the reproduction locationstoring memory 743.

Next, a method for recording a file containing AV data on the disk 1using the information recording/reproducing system 700 illustrated inFIG. 7 will be described below.

FIG. 8 illustrates the steps of the recording method.

In FIG. 8, it is assumed that the file management information for a file("AV₋₋ FILE") recorded on the rewritable disk 1 is read out when thedisk 1 is inserted into the disk recording/reproducing drive 720, theninterpreted by the file management information interpretation section713, and stored in the upper level control unit 710.

Moreover, in FIG. 8, reference numeral 81 denotes operations performedby the upper level control unit 710, reference numeral 82 denotes thoseperformed by the disk recording/reproducing drive 720, and referencenumeral 83 denotes instructions, data and operation results flowingthrough the I/F protocol between the upper level control unit 710 andthe disk recording/reproducing drive 720.

(Step 801) The upper level control unit 710 controls the AV data inputsection 770 to start an AV data receiving operation. The AV datareceived by the AV data input section 770 is converted into digital dataat the AV data input section 770, and then transmitted through the I/Obus 780 to be stored in the data buffer memory 714.

(Step 802) Prior to an AV data recording operation, the recording areaallocation section 711 of the upper level control unit 710 obtainsinformation indicating a free area of the rewritable disk 1 from thefile management information interpretation section 713, and allocatesthe free area as a recording area. The recording area allocation section711 performs the area allocation operation in view of the size of thearea to be allocated and the physical distance from one area to anotherso that the AV data can be smoothly reproduced.

(Step 803) The skip recording instruction issuing section 716 of theupper level control unit 710 obtains location information of the areaallocated by the recording area allocation section 711, and issues a"SKIP WRITE" command (a skip recording instruction) to the diskrecording/reproducing drive 720. The skip recording instruction issuingsection 716 specifies the location information of the area allocated bythe recording area allocation section 711 and the recording sizeinformation, as parameters for the "SKIP WRITE" command. Following the"SKIP WRITE" command, data having a size as specified by this command istransferred from the data buffer memory 714 to the diskrecording/reproducing drive 720.

Each of FIGS. 23A and 23B illustrates an exemplary format for the "SKIPWRITE" command.

FIG. 23A illustrates an exemplary format for the "SKIP WRITE" commandsuch that it is possible to specify both the allocated area and the sizeof the data to be recorded through a single issuance of the command.Byte 0 stores a unique instruction code indicating that it is a "SKIPWRITE" command. Bytes 2-5 store an LSN indicating the leading sector ofthe allocated area. Bytes 6-7 store the number of sectors correspondingto the size of the data to be recorded (data length). Bytes 8-9 storethe number of sectors corresponding to the size of the allocated area(area length).

FIG. 23B illustrates an exemplary format for the "SKIP WRITE" commandsuch that the allocated area and the size of the data to be recorded canbe specified through a number of issuances of the command. Byte 0 storesa unique instruction code indicating that it is a "SKIP WRITE" command.An operation option is provided at bit 0 of byte 1. The operation optionbeing "1" indicates that the command specifies the allocated area. Theoperation option being "0" indicates that the command specifies the sizeof the data to be recorded. When the operation option is "1", bytes 2-5store an LSN indicating the leading sector of the allocated area, whilebytes 7-8 store the number of sectors corresponding to the size of theallocated area (area length). When the operation option is "0", bytes7-8 store the number of sectors corresponding to the size of the data tobe recorded (data length).

The command formats illustrated in FIGS. 23A and 23B are merely examplesof the format for the "SKIP WRITE" command. The "SKIP WRITE" command mayemploy any other format as long as the location information of theallocated area and the size information of the data to be recorded canbe specified.

(Step 804) Upon receipt of the "SKIP WRITE" command issued from theupper level control unit 710, the skip recording instruction processingsection 722 of the disk recording/reproducing drive 720 initializes therecording control information memory 735 and the recording locationstoring memory 733 according to the "SKIP WRITE" command, and activatesthe skip recording controlling section 732. The skip recordingcontrolling section 732 records data from the recording data storingmemory 736 into non-defective blocks of the disk 1 while detecting anydefective block (including newly-found defective blocks and those whichhave already been registered in the SDL) using the defective areadetection section 731. Each time a defective block is detected, thenumber of blocks which can be skipped (stored in the recording controlinformation memory 735) is decremented by one, and the location of thedefective block is stored in the recording location storing memory 733.Each time a block is successfully recorded, the number of blocks whichhave been recorded (stored in the recording control information memory735) is incremented by one. When the recording operation for the numberof blocks requested is completed before the number of blocks which canbe skipped becomes 0 or less, the process is normally terminated. Whenit is instructed to verify reproduced data after the recordingoperation, the defective blocks detected by the defective area detectionsection 731, as well as those detected by the data verifying section734, are skipped.

As described above, the skip recording controlling section 732 continuesthe recording operation until all data is normally recorded whileskipping the defective areas detected during the recording operation andstoring the skipped location information.

(Step 805) The disk recording/reproducing drive 720, having performedthe skip recording operation, returns a "complete" status to the upperlevel control unit 710.

(Step 806) The recording location request instruction issuing section717 of the upper level control unit 710 issues to the diskrecording/reproducing drive 720 a "REPORT SKIPPED ADDRESS" command forinquiring location information of the defective areas skipped in theskip recording operation in step 804.

FIG. 24A illustrates an exemplary format for the "REPORT SKIPPEDADDRESS" command. Byte 0 stores a unique instruction code indicatingthat it is a "REPORT SKIPPED ADDRESS" command. Bytes 7-8 store an upperlimit value for the size of data to be reported.

FIG. 24B illustrates an exemplary format for data which is reported inresponse to the "REPORT SKIPPED ADDRESS" command. Bytes 0-1 store thenumber of location information points to be reported. For byte 4 andthereafter, each set of four bytes stores location information of askipped defective area.

The command and data formats illustrated in FIGS. 24A and 24B are merelyexemplary. The command and the data may employ any other format as longas it is possible to inquire the location information of the skippeddefective areas.

(Step 812) The skip location recording section 737 registers, as an SDLentry, the location information of the defective area which was storedin the recording location storing memory 733 during the skip recordingoperation in step 804. Thus, the defect management information isupdated.

(Step 807) Upon receipt of the "REPORT SKIPPED ADDRESS" command, therecording location request instruction processing section 723 of thedisk recording/reproducing drive 720 returns, as skipped address data,the location information of the defective area which was stored in therecording location storing memory 733 during the skip recordingoperation in step 804.

(Step 808) Upon receipt of the skipped address data, the file managementinformation creation section 712 of the upper level control unit 710creates file management information. The file management informationcreation section 712 creates the file entry of the AV file whiledetermining that data has been recorded in areas other than the skippedareas as indicated by the skipped address data, and sets the bit of thefree space management information corresponding to each area in whichdata is determined to be recorded to "1" ("used"). The file managementinformation creation section 712 further specifies the skipped areasfrom the skipped address data returned in step 807, and sets the bit ofthe free space management information corresponding to each of theskipped areas to "0" ("free"). When the end of the file extent lies inthe middle of (but not at the end of) an ECC block, the file managementinformation creation section 712 registers the remaining area of the ECCblock as a padding extent. At this time, the extent type of the paddingextent is set to "1", indicating that it is a padding extent, and setsthe bit of the free space management information corresponding to thepadding extent areas to "1" ("used"). Then, the file managementinformation creation section 712 stores the created file managementinformation in the data buffer memory 714 for recording the filemanagement information on the rewritable disk 1.

(Step 809) The upper level control unit 710 issues a "WRITE" commandrequesting the disk recording/reproducing drive 720 to record, by aconventional recording method, the file management information which isstored in the data buffer memory 714. As parameters for the "WRITE"command, the LSN at which the recording operation is started and thenumber of sectors to be recorded are specified.

(Step 810) The disk recording/reproducing drive 720 receives the "WRITE"command and records the file management information on the disk 1according to a conventional recording method. Any defective area whichis detected during the recording operation in response to the "WRITE"command is replaced by a conventional replacement method.

(Step 811) The disk recording/reproducing drive 720 having recorded allof the data specified by the "WRITE" command returns a "complete" statusto the upper level control unit 710.

Step 812 may be performed immediately after step 804, or when apredetermined period of time has passed after performing step 811 whileno request has been issued from the upper level control unit 710.

As described above, the disk recording/reproducing drive 720 detects andskips defective areas while recording AV data which requires real timeprocessing on the disk 1. No replacement area is allocated to theskipped defective areas, but the location of the skipped defective areasis recorded in the defect management information area 4b of therewritable disk 1.

Next, a method for reproducing a file containing AV data which isrecorded on the disk 1 by using the information recording/reproducingsystem 700 illustrated in FIG. 7 will be described below.

FIG. 9 illustrates the steps of the reproducing method.

In FIG. 9, reference numeral 91 denotes operations performed by theupper level control unit 710, reference numeral 92 denotes thoseperformed by the disk recording/reproducing drive 720, and referencenumeral 93 denotes instructions, data and operation results flowingthrough the I/F protocol between the upper level control unit 710 andthe disk recording/reproducing drive 720.

(Step 901) Upon loading of the rewritable disk 1 and when updating thedefect management information, the disk recording/reproducing drive 720reads out the defect management information on the rewritable disk 1using the skip location reading section 747, and stores it in thereproduction location storing memory 743.

(Step 902) The recording area allocation section 711 of the upper levelcontrol unit 710 allocates the AV data recording area (which haspreviously been allocated in step 802) as a reproducing area.

(Step 903) The skip reproducing instruction issuing section 718 of theupper level control unit 710 obtains the location information of thearea allocated in step 902, and issues a "SKIP READ" command (a skipreproducing instruction) to the disk recording/reproducing drive 720.The skip reproducing instruction issuing section 718 specifies thelocation information of the area allocated in step 902 and thereproducing size information, as parameters for the "SKIP READ" command.Following the "SKIP READ" command, data having a size as specified bythis command is transferred from the disk recording/reproducing drive720 to the data buffer memory 714 (step 905).

The "SKIP READ" command can be defined similarly as the "SKIP WRITE"command. For example, a unique instruction code indicating that it is a"SKIP READ" command may be set in byte 0 in the format illustrated inFIG. 23A or 23B. This is merely an example of the format for the "SKIPREAD" command. The "SKIP READ" command may employ any other format aslong as the location information of the allocated area and the sizeinformation of the data to be reproduced can be specified.

(Step 904) Upon receipt of the "SKIP READ" command issued from the upperlevel control unit 710, the skip reproducing instruction processingsection 724 of the disk recording/reproducing drive 720 initializes thereproduction control information memory 745 according to the "SKIP READ"command, and activates the skip reproduction controlling section 742.The skip reproduction controlling section 742 reproduces data fromnon-defective blocks of the disk 1 with reference to the reproductionlocation storing memory 743, and stores the reproduced data in theread-out data storing memory 746. Each time a block is successfullyreproduced, the number of blocks which have been reproduced (stored inthe reproduction control information memory 745) is incremented by one.When the reproducing operation for the number of blocks requested iscompleted, the process is normally terminated.

(Step 905) The AV data stored in the read-out data storing memory 746 instep 904 is transferred to the upper level control unit 710.

(Step 906) The received AV data is transferred to the AV data outputsection 760. The AV data output section 760 converts input data to ananalog AV signal and outputs the analog AV signal.

(Step 907) The disk recording/reproducing drive 720 having performed theskip reproducing operation returns a "complete" status to the upperlevel control unit 710.

As described above, the disk recording/reproducing drive 720 referencesthe defect management information when reproducing AV data whichrequires real time processing, whereby the disk recording/reproducingdrive 720 can reproduce the AV data while skipping defective areas onthe rewritable disk 1.

(Embodiment 3)

Another embodiment of an information recording/reproducing system forrecording information on, or reproducing recorded information from, thedisk 1 as described in Embodiment 1 above will now be described withreference to the figures.

FIG. 10 is a block diagram illustrating a structure of a diskrecording/reproducing drive 1020 according to Embodiment 3 of thepresent invention. The disk recording/reproducing drive 1020 isconnected to the upper level control unit 710 illustrated in FIG. 7 viathe I/O bus 780.

The disk recording/reproducing drive 1020 includes a microprocessor inwhich a control program and an arithmetic memory are provided. The diskrecording/reproducing drive 1020 is made of a mechanical section, asignal processing circuit, etc., which are controlled by themicroprocessor. The disk recording/reproducing drive 1020 operativelyincludes: an instruction processing section 1021 for processing aninstruction from the upper level control unit 710; a recording controlsection 1030 for controlling the recording operation on the rewritabledisk 1; a reproduction controlling section 1040 for controlling thereproducing operation from the rewritable disk 1; a replacementinformation storing memory 1050 for storing information of defectiveblocks and information of replacement blocks allocated thereto; and adata buffer 1060 for temporarily storing recording data and reproduceddata.

The instruction processing section 1021 includes: a recordinginstruction processing section 1022 for processing a normal recordinginstruction which does not involve a skip recording operation; and areproducing instruction processing section 1024 for processing a normalreproducing instruction which does not involve a skip reproducingoperation.

The recording control section 1030 includes: a data synthesis section1031 for converting sector-wise recording data (recording data which isarranged in the unit of sectors) into ECC block-wise recording data(recording data which is arranged in the unit of ECC blocks); a blockrecording section 1032 for recording the ECC block-wise data on therewritable disk 1; a replacement allocation section 1033 for allocatinga spare block for replacing a defective block; an SDL update section1034 for recording the contents of the replacement information storingmemory 1050 in the SDL on the rewritable disk 1: and an ECC fractionchecking section 1035.

The reproduction controlling section 1040 includes: a "0" data fillingsection 1041 for rewriting a portion of the data buffer 1060 with "0"s,a block reproducing section 1042 for reproducing ECC block-wise datafrom the rewritable disk 1; an SDL reading section 1043 for storing thecontents reproduced from the SDL on the rewritable disk 1 in thereplacement information storing memory 1050; and an ECC fractionadjustment section 1044.

Next, a method for reproducing normal computer data (not real time data)recorded on the disk 1 by using the disk recording/reproducing drive1020 illustrated in FIG. 10 will be described below.

FIG. 11 illustrates the steps of the reproducing method.

In FIG. 11, reference numeral 111 denotes operations performed by theupper level control unit 710, reference numeral 112 denotes thoseperformed by the disk recording/reproducing drive 1020, and referencenumeral 113 denotes instructions, data and operation results flowingthrough the I/F protocol between the upper level control unit 710 andthe disk recording/reproducing drive 720. The reproducing operationperformed by the disk recording/reproducing drive 1020 will be describedonly briefly below, and detailed description thereof will be providedlater.

(Step 1101) Upon loading of the rewritable disk 1 and when updating thedefect management information, the disk recording/reproducing drive 1020reads out the defect management information on the rewritable disk 1using the SDL reading section 1043, and stores it in the replacementinformation storing memory 1050.

(Step 1102) The upper level control unit 710 analyzes the file structureso as to determine the location of an area where computer data isstored.

(Step 1103) The upper level control unit 710 obtains informationindicating the location of the area which has been determined in step1102, and issues a "READ" command (a normal reproducing instruction) tothe disk recording/reproducing drive 1020.

(Step 1104) Upon receipt of the "READ" command, the reproducinginstruction processing section 1024 of the disk recording/reproducingdrive 1020 reads out the specified data from the rewritable disk 1, andtransfers the data to the upper level control unit 710 (step 1105). Thedisk recording/reproducing drive 1020 having transferred all of the datarequested returns a "complete" status (step 1107).

(Step 1106) The reproduced data is transferred via the I/F protocol andstored in the data buffer memory 714 of the upper level control unit710.

As the upper level control unit 710 receives the "complete" status viathe I/F protocol, the data stored in the data buffer memory 714 is usedas computer data.

FIG. 12 is a flow chart illustrating a procedure of the reproducingoperation (step 1104 in FIG. 11) performed by the diskrecording/reproducing drive 1020.

The area requested to be reproduced is specified by sectors. The ECCfraction adjustment section 1044 determines the ECC blocks that includethe area requested to be reproduced (step 1201). Assuming that S is theLSN of the leading sector of the area requested to be reproduced, N isthe number of sectors of the area requested to be reproduced, and E isthe number of sectors of one ECC block, then, the LSN (S₋₋ ECC) of theleading sector of the area which needs to be reproduced and the numberof sectors (N₋₋ ECC) of the area which needs to be reproduced in view ofthe ECC block can be determined by the following expressions.

    S.sub.-- ECC=[S/E]×E

    N.sub.-- ECC=[(S+N+E-1)/E]×E-S.sub.-- ECC

where [α] denotes the largest integer not exceeding α.

If all of the blocks which need to be reproduced have not completelybeen stored in the data buffer 1060 (step 1202), the SLD is referenced(step 1203). If the block to be reproduced is not registered in the SDLas a defective block, the process proceeds to step 1204. If the block tobe reproduced is registered in the SDL as a defective block to which areplacement spare block has been allocated, the process proceeds to step1205. If the block to be reproduced is registered in the SDL as adefective block to which a replacement spare block has not beenallocated, the process proceeds to step 1206.

In step 1204, the block to be reproduced is reproduced. In step 1205,the replacement spare block is reproduced instead of the block to bereproduced. In step 1206, "0" data filling section 1041 create the ECCblock filled with "0" instead of reproducing the data from disk 1. TheECC block filled with "0"s is created by, for example, filling apredetermined area of the data buffer 1060 with "0"s.

If all of the blocks which need to be reproduced have completely beenstored in the data buffer 1060 (step 1202), the data stored in the databuffer 1060 is transferred to the upper level control unit 710 (step1207), and the process is terminated.

Where the block to be reproduced is registered in the SDL as a defectiveblock to which a replacement spare block has not been allocated, it isalternatively possible to immediately determine a reproduction errorwhile reporting the error to the upper level control unit 710, ratherthan creating an ECC block filled with "0"s as the reproduced data forthe defective block. When a reproduction error is reported to the upperlevel control unit 710, the upper level control unit 710 instructs adata recording operation for the block, thus performing a replacementoperation which will be described later. As a result, the defectiveblock to replaced by a reproducible spare block in the logical volumespace.

As described above, when it is requested to reproduce data from adefective block to which a replacement spare block has not beenallocated, the disk recording/reproducing drive 1020 returns data filledwith "0"s as reproduced data, without reporting a reproduction error.Alternatively, when it is requested to reproduce data from a defectiveblock to which a replacement spare block has not been allocated, thedisk recording/reproducing drive 1020 may report a reproduction errorwithout wasting time for a reproducing operation which is likely tofail.

The steps of the method for recording normal computer data (not realtime data) on the disk 1 are substantially the same as those of thereproducing method as illustrated in FIG. 11, except that a "WRITE"command is issued instead of a "READ" command, and recording data istransmitted in the reverse direction instead of reproduced data.

FIG. 13 is a flow chart illustrating a procedure of the recordingoperation performed by the disk recording/reproducing drive 1020.

The disk recording/reproducing drive 1020 receives data to be recordedfrom the upper level control unit 710, and stores it in the data buffer1060 (step 1301).

The area requested to be recorded is specified by sectors. ECC fractionchecking section 1035 determines the ECC blocks that include the arearequested to be reproduced.

Furthermore, the ECC fraction checking section 1035 determines toperform a buffering operation for the fraction according to existence ofthe fraction. Such a buffering operation is accomplished by steps1202-1206 which are surrounded by a broken line in FIG. 12.

If the leading sector of the area requested to be recorded is not theleading sector of an ECC block (i.e., if S≠S₋₋ ECC) (step 1303), abuffering operation is performed for the ECC block including the leadingsector (step 1304).

If the last sector of the area requested to be recorded is not the lastsector of an ECC block (i.e., if S+N≠S₋₋ ECC+N₋₋ ECC) (step 1305), abuffering operation is performed for the ECC block including the lastsector (step 1306).

The data synthesis section 1031 synthesizes the data obtained in step1301 with the data obtained in steps 1303-1306. As a result, recordingdata corresponding to all of the ECC blocks to be recorded is providedin the data buffer 1060 (step 1307).

If all of the blocks which need to be recorded have not completely beenrecorded on the rewritable disk 1 (step 1308), the SDL is referenced(step 1309). As a result, if the block to be recorded is not registeredin the SDL as a defective block, the process proceeds to step 1310. Ifthe block to be recorded is registered in the SDL as a defective blockto which a replacement spare block has been allocated, the processproceeds to step 1312. If the block to be recorded is registered in theSDL as a defective block to which a replacement spare block has not beenallocated, the process proceeds to step 1311.

In step 1310, data is recorded in a block to be recorded. In step 1312,data is recorded in a replacement spare block instead of the block to berecorded. In step 1311, the replacement allocation section 1022allocates a replacement spare block to the defective block, then thedata is recorded in the replacement spare block (step 1312).

There are two methods for allocating a replacement spare block for adefective block instep 1311. As described above with reference to FIGS.1C to 1E, it is possible to determine whether a replacement block waspreviously allocated to a defective block based on the value of thefield 22c storing the location of the replacement block. If noreplacement block was previously allocated to the defective block (e.g.,if the value of the field 22c is "0"), a free spare block is newlyallocated to the defective block. If a replacement block was previouslyallocated to the defective block (e.g., if an address of a previouslyallocated replacement block is described in the field 22c), the samereplacement block as that which was previously allocated to thedefective block is allocated again to the defective block.

If all of the blocks which need to be recorded have not completely beenrecorded on the rewritable disk 1 (step 1308), it is determined whetherthe SDL needs to be updated (step 1313). For example, where areplacement spare block has been newly allocated to the defective blockin step 1311, the SDL needs to be updated. If the SDL needs to beupdated, the SDL is updated (step 1314), and the process is terminated.

As described above, when the disk recording/reproducing drive 1020 isrequested to record data in a defective block to which a replacementspare block has not been allocated, a replacement spare block is firstallocated to the defective block, after which the data is recorded inthe replacement spare block. In this way, the recording data is recordedon the disk 1 by ECC blocks. Any ECC block fraction is adjusted by, forexample, filling the fraction with "0"s.

(Embodiment 4)

Still another embodiment of an information recording/reproducing systemfor recording information on, or reproducing recorded information from,the disk 1 as described in Embodiment 1 above will now be described withreference to the figures.

FIG. 14 is a block diagram illustrating a structure of a diskrecording/reproducing drive 1420 according to Embodiment 4 of thepresent invention. The disk recording/reproducing drive 1420 isconnected to the upper level control unit 710 illustrated in FIG. 7 viathe I/O bus 780. Elements in FIG. 14 having like reference numerals tothose shown in FIG. 10 will not further be described.

The disk recording/reproducing drive 1420 operatively includes: aninstruction processing section 1021 for processing an instruction fromthe upper level control unit 710; a recording control section 1430 forcontrolling the recording operation on the rewritable disk 1; areproduction controlling section 1440 for controlling the reproducingoperation from the rewritable disk 1; a replacement information storingmemory 1050 for storing information of defective blocks and informationof replacement blocks allocated thereto; and a data buffer 1060 fortemporarily storing recording data and reproduced data.

As compared to the recording control section 1030 described inEmbodiment 3 above, the recording control section 1430 additionallyincludes a remaining spare block detection section 1437 for determiningthe number of spare blocks remaining available.

As compared to the reproduction controlling section 1040 described inEmbodiment 3 above, the reproduction controlling section 1440 does notinclude the "0" data filling section 1041, but rather includes a sectorreproducing section 1441 for reproducing data recorded on the rewritabledisk 1 by sectors.

The steps of the method for reproducing normal computer data (not realtime data) are the same as those described in Embodiment 3 above (FIG.11), and therefore will not further be described below.

FIG. 15 is a flow chart illustrating a procedure of the reproducingoperation performed by the disk recording/reproducing drive 1420. Theprocedure illustrated in FIG. 15 is different from that illustrated inFIG. 12 for the following reason. If an ECC block to be reproduced isregistered in the SDL as a defective block to which a replacement spareblock has not been allocated (step 1503), the sector reproducing section1441 performs a sector-wise reproducing operation for each of sectorsincluded in the ECC block to be reproduced (step 1507).

Referring to FIG. 22C, the sector-wise reproducing operation will bedescribed below. Since the inner code parity PI is obtained bycalculating error correcting codes for each row (in the lateraldirection), the inner code parities PI correctly correspond to the maindata for each sector (i.e., in FIG. 22c, the hatching direction for themain data area matches that for the inner code parities PI). Therefore,errors can be corrected with the inner code parities PI, though theerror correction capability is reduced. For example, when a datarecording operation stops at a boundary between sectors due to adefective ID, the error may be corrected with a high probability evenwith the inner code parities PI alone.

As described above, the disk recording/reproducing drive 1420 canreproduce a defective block to which a replacement spare block has notbeen allocated by recovering correct data from the overwritten sectorsin the defective block while recovering data previously recorded in theother sectors in the defective block which have not been overwritten.

FIG. 16 is a flow chart illustrating a procedure of the recordingoperation performed by the disk recording/reproducing drive 1420. Theprocedure illustrated in FIG. 16 is different from that illustrated inFIG. 13 for the following reason. If a block-wise data recordingoperation on the rewritable disk 1 fails, the block for which therecording operation failed is registered in the SDL as a defectiveblock. Moreover, before allocating a replacement spare block to adefective block, the process is terminated with an error if there is nospare block available.

The disk recording/reproducing drive 1420 receives data to be recordedfrom the upper level control unit 710, and stores it in the data buffer1060 (step 1601).

The area requested to be recorded is specified by sectors. An areaincluding the area requested to be recorded is determined by ECC blocks(step 1602).

If there is any ECC block fraction, a buffering operation for thefraction is performed. Such a buffering operation is accomplished bysteps 1502-1506 which are surrounded by a broken line in FIG. 15.

By synthesizing the data obtained in step 1601 with the data obtained insteps 1603-1606, recording data corresponding to all of the ECC blocksrequired for the recording operation is provided in the data buffer 1060(step 1607).

If all of the blocks which need to be recorded have not completely beenrecorded on the rewritable disk 1 (step 1608), the SDL is referenced(step 1609). As a result, if the block to be recorded is not registeredin the SDL as a defective block, the process proceeds to step 1610. Ifthe block to be recorded is registered in the SDL as a defective blockto which a replacement spare block has been allocated, the processproceeds to step 1612. If the block to be recorded is registered in theSDL as a defective block to which a replacement spare block has not beenallocated, the process proceeds to step 1615.

In step 1610, data is recorded in a block to be recorded. In step 1612,data is recorded in a replacement spare block instead of the block to berecorded. In step 1615, the remaining spare block detection section 1437determines whether there are any available spare blocks in the sparearea. If there is an available spare block in the spare area, thereplacement spare block is allocated to the block to be recorded (step1611), and data is recorded in the replacement spare block (step 1612).

In step 1610 or step 1612, if block-wise data recording operation on therewritable disk 1 fails (step 1616), the block for which the recordingoperation failed is registered in the SDL as a defective block (step1617), and the process returns to step 1609 to retry the recordingoperation.

If all of the blocks which need to be recorded have completely beenstored on the rewritable disk 1 (step 1608), or if there is no availablespare block in the spare area (step 1615), it is determined whether theSDL needs to be updated (step 1613). For example, where a replacementspare block has been newly allocated to the defective block in step1611, the SDL needs to be updated. Also where a defective block whichhas been detected in step 1617 is newly registered in the SDL, the SDLneeds to be updated. If the SDL needs to be updated, the SDL is updated(step 1614), and the process is terminated.

Where the process is terminated after all of the blocks have completelybeen recorded (step 1608), the termination is determined to be normal.Where the process is terminated after spare area exhaustion (step 1615),the termination is determined to be a termination with an error.

As described above, the disk recording/reproducing drive 1420 alwaysregisters a detected defective block in the defect managementinformation area even if no spare block is available for replacement.Moreover, when the disk recording/reproducing drive 1420 is requested torecord data in a defective block to which a replacement spare block hasnot been allocated, the drive can synthesize the record date receivedfrom the upper level control unit with the correct data from theoverwritten sector and the previous data from the other sectors in thedefective block in which the terminating occurred during recording. Suchsynthesized recording data is recorded on the disk 1 by ECC blocks.

While the parameters transferred by the I/F protocol include the areastart location, the size, etc., in Embodiments 2, 3 and 4, it isapparent to those skilled in the art that the parameters may be anyother parameters as long as they can be subjected to an arithmeticoperation to obtain the same information. Moreover, the datatransmission between the upper level control unit and the diskrecording/reproducing drive, and that between the diskrecording/reproducing drive and the rewritable disk, may be sequentialor parallel. Furthermore, it is also apparent to those skilled in theart that when the upper level control unit and the diskrecording/reproducing drive are integrated together, the parameters maybe transferred by using a shared memory, or the like.

According to the information recording medium of the present invention,defect management information including status information whichindicates whether a defective area is replaced by a replacement area isrecorded in the defect management information area. With this statusinformation, it is possible to manage the status where a defective areahas been detected but is not replaced by a replacement area.

When a defective area is detected while recording data which requiresreal time processing (e.g., AV data) on the information recordingmedium, the defective area is skipped. The location of the defectivearea and status information indicating that the defective area is notreplaced by a replacement area are written in the defect managementinformation area. When it is requested to record data which does notrequire real time processing (e.g., non-AV data) in the defective area,a replacement area is allocated to the defective area without performinga read modified write operation, thereby successfully performing therequested recording operation. Moreover, a replacement area is notallocated to the defective area until it is actually requested to recorddata in the defective area. This provides an advantage in that noreplacement area is wasted.

Where a spare area is expandable, the spare area may temporarily run outof available replacement areas. When no replacement area can beallocated to a detected defective area because the spare area istemporarily out of available replacement areas, the location of thedefective area and status information indicating that the defective areais not replaced by a replacement area are written in the defectmanagement information area. After the spare area is expanded and areplacement area is made available, the replacement area is allocated tothe defective area. The location of the replacement area is written inthe defect management information area.

According to the information recording method and the informationrecording apparatus of the present invention, defect managementinformation, including status information which indicates whether adefective area is replaced by a replacement area, is recorded in thedefect management information area. Thus, effects similar to thosedescribed above are obtained.

According to the information reproducing apparatus of the presentinvention, it is determined whether a defective area is replaced by areplacement area with reference to the status information, so as tocontrol the reproducing operation of user data according to thedetermination. Thus, user data can be reproduced even if a defectivearea is not replaced by a replacement area.

When it is requested to reproduce data from a defective area to which areplacement area has not been allocated, user data may be reproducedwhile skipping the defective area. Alternatively, data having a fixedvalue (e.g., data filled with "0"s) may be output as reproduced dataobtained by reproducing the defective area. Alternatively, correcteddata may be reproduced by not performing error correction with errorcorrecting codes which expand over a plurality of sectors, while onlyperforming error correction with error correcting codes which do notexpand over a plurality of sectors (e.g., error correcting codes withineach sector).

Various other modifications will be apparent to and can be readily madeby those skilled in the art without departing from the scope and spiritof this invention. Accordingly, it is not intended that the scope of theclaims appended hereto be limited to the description as set forthherein, but rather that the claims be broadly construed.

What is claimed is:
 1. An information recording medium, comprising:avolume space for recording user data; an expandable spare area includinga replacement area which is usable in place of a defective area includedin the volume space; and a defect management information area forrecording defect management information for managing the defective area,wherein:the defect management information includes status informationindicating whether the defective area is replaced by the replacementarea, when there are no available replacement area included in the sparearea temporarily, the status information indicating that the defectivearea is not replaced by the replacement area is written into the defectmanagement information area.
 2. A method for recording information on aninformation recording medium including a volume space for recording userdata; and expandable spare area including a replacement area which isusable in place of a defective area included in the volume space; and adefect management information area for recording defect managementinformation for managing the defective area, the method comprising thesteps of:detecting the defective area; recording status informationindicating whether the defective area is replaced by the replacementarea in the defect management information; and detecting that there areno available replacement area included in the spare area temporarily,wherein:when there are no available replacement area included in thespare area temporarily, the status information indicating that thedefective area is not replaced by the replacement area is written intothe defect management information area.
 3. An apparatus for recordinginformation on an information recording medium including a volume spacefor recording user data; an expandable spare area including areplacement area which is usable in place of a defective area includedin the volume space; and a defect management information area forrecording defect management information for managing the defective area,the apparatus comprising:a first detection section for detecting thedefective area; a recording section for recording status informationindicating whether the defective area is replaced by the replacementarea in the defect management information; and a second detectionsection for detecting that there are no available replacement areaincluded in the spare area temporarily, wherein:when there are noavailable replacement area included in the spare area temporarily, therecording section writes the status information indicating that thedefective area is not replaced by the replacement area into the defectmanagement information area.